The surgical treatment of symptomatic Arnold-Chiari malformation type I (CM-I) typically involves decompression of the posterior cranial fossa. A full-endoscopic approach is emerging as an alternative to traditional microsurgical techniques. However, this method presents challenges in intraoperative assessment of the decompression extent, potentially resulting in inadequate decompression. In neurosurgery, ultrasound is gaining increasing importance, as it avoids ionizing radiation and enables real-time examination. The aim of this anatomical study is to evaluate the suitability of ultrasound for assessing defect size compared to radiography and CT during uniportal full-endoscopic decompression of the posterior fossa. Six fresh-frozen adult human cadavers underwent endoscopic decompression of the posterior fossa. The endoscope used featured an oval shaft with a diameter of 9.3 mm, a working length of 177 mm, a 20° viewing angle, and an eccentric 5.6 mm working channel. Computed tomography (CT), X-rays, and ultrasound images were obtained before and after decompression for measurement purposes. The average endoscopic decompression in the sagittal plane as measured by ultrasound was 26 ± 2 mm, with fluoroscopy 27 ± 1 mm and using CT 26 ± 1 mm. A statistically significant Pearson correlation was found between ultrasound and CT (r = 0.94, p < 0.01); between ultrasound and fluoroscopy (r = 0.9, p < 0.05); and between fluoroscopy and CT (r = 0.8, p < 0.05). The average endoscopic decompression in the axial plane as measured by ultrasound was 37 ± 2 mm, with fluoroscopy 26 ± 2 mm and using CT 36 ± 1 mm. A statistically significant Pearson correlation was found only between ultrasound and CT (r = 0.95, p < 0.01). The full-endoscopic approach enables effective decompression of the posterior fossa in an experimental setup. Intraoperative ultrasound proves reliable in assessing the extent of decompression, showing good correlation with X-rays and CT. This technique holds promise for wider use in CM-I treatment, particularly in pediatric neurosurgery, where ultrasound offers a radiation-free method for intraoperative evaluation of defect size.

Chiari Malformation Type I (CM-I) is characterized by cerebellar tonsil herniation, often requiring posterior fossa decompression. However, when cerebrospinal fluid flow remains obstructed, additional interventions such as endoscopic third ventriculostomy (ETV) or ventriculoperitoneal shunting (VPS) may be necessary. Despite the frequent use of ETV in CM-I cases, evidence supporting its efficacy remains limited. To address this gap, we conducted an updated systematic review and meta-analysis to evaluate ETV outcomes in patients with CM-I. We conducted a comprehensive search of the Medline, Embase, and Web of Science databases, adhering to PRISMA guidelines. The inclusion criteria for studies required a minimum of three patients and focused on outcomes such as symptom improvement, Endoscopic Third Ventriculostomy success, good clinical outcomes and complications. From 502 initially identified studies, 10 were selected, involving 100 patients, including 30 children across four studies, with a median follow-up of 42 months. Using random effects models, the combined analysis showed a 98 % (95 % CI: 93 % - 100 %, I2 = 22 %) Favorable clinical outcomes rate. Specifically, symptom improvement related to hydrocephalus was observed at 97 % (95 % CI: 0.88---1.00, I2 = 16), and syrinx improvement at 78 % (95 % CI: 61 % - 96 %, I2 = 21 %). Complication rates were 3 % (95 % CI: 0 % - 8 %, I2 = 0 %) overall and 0 % (95 % CI: 0 % - 7 %, I2 = 0 %) in the pediatric population. The ETV success rate was 92 % (95 % CI: 87 % - 98 %, I2 = 29 %). Endoscopic Third Ventriculostomy shows promising efficacy in treating hydrocephalus and syringomyelia, with minimal complications. Its potential as a less invasive alternative to shunts underscores the significance of our study.

Tracheostomy decannulation in patients with neuromuscular disease presents significant challenges due to impaired airway clearance, pharyngolaryngeal hypotonia, and chronic hypoventilation. Polysomnography (PSG) may provide an objective assessment of ventilatory stability and support safe decision-making. We describe a 54-year-old woman with sequelae of Arnold-Chiari malformation type I, syringomyelia, and tetraplegia (AIS D, neurological level C1), who developed chronic respiratory insufficiency requiring tracheostomy. Despite achieving nocturnal normocapnia with non-invasive ventilation, she exhibited persistent daytime hypercapnia and severely impaired cough. A capped tracheostomy PSG performed under nasal-mask non-invasive ventilation demonstrated no worsening of baseline hypoventilation, confirming ventilatory stability and supporting decannulation readiness. Anxiety delayed the procedure, but multidisciplinary evaluation continued to indicate safety for future decannulation. This case highlights the utility of PSG in the assessment of complex neuromuscular patients with multifactorial hypoventilation, where standard pulmonary function testing may be limited.

To report a rare case of coexisting Arnold-Chiari malformation type I (CM-I) and osteopetrosis revealed by incidental optic disc elevation, and to review the literature on similar presentations to highlight diagnostic challenges and the role of fundoscopic examination. We describe a 22-year-old female with incidental bilateral optic disc edema discovered during ophthalmoscopy training. Despite normal visual acuity and absence of visual symptoms, further imaging revealed Chiari I malformation and osteopetrosis. Optical coherence tomography and fluorescein angiography showed disc elevation without leakage, and no lumbar puncture was performed due to herniation risk. A systematic review of 17 publications encompassing 22 cases was conducted to assess the prevalence and documentation of optic disc findings in similar cases. The patient underwent suboccipital decompression and C1 laminoplasty, resulting in headache resolution but persistent optic disc elevation at 3-year follow-up. Literature review revealed that optic disc findings were underreported, with only 13.7% of cases showing papilledema and 40.9% lacking fundus documentation. No prior reports described anomalous optic discs mimicking papilledema in this dual pathology. This case highlights the diagnostic value of fundoscopic examination in uncovering serious underlying conditions. Anomalous optic discs mimicking papilledema may represent an underrecognized manifestation in patients with Chiari I malformation and osteopetrosis.

Arnold-Chiari Malformation Type I (ACM-I) is a congenital disorder that can lead to severe neurological symptoms. While decompression surgery is the standard treatment, postoperative complications such as cerebrospinal fluid (CSF) leakage and infections can result in critical outcomes. Here, we report a case of septic shock following decompression surgery in a patient with ACM-I, emphasizing the challenges in postoperative critical care management. A 45-year-old woman with rheumatoid arthritis and progressive neurological symptoms underwent decompression surgery for ACM-I. On postoperative day five, CSF leakage was noted at the surgical site, accompanied by fever and leukocytosis. Despite broad-spectrum antibiotics, the patient developed septic shock, requiring mechanical ventilation and vasopressor support. CSF cultures revealed Acinetobacter baumannii infection, necessitating surgical debridement and intrathecal colistin. Despite aggressive management, the patient succumbed to septic shock. This case highlights the critical importance of early detection and aggressive management of postoperative infections in neurosurgical patients. The occurrence of CSF leakage and subsequent septic shock underscores the need for meticulous postoperative monitoring to prevent fatal complications. Timely intervention, including early microbiological assessment and individualized antibiotic therapy, is essential for improving outcomes in high-risk patients.